IF EXIST JPack.toc.3.0 goto conv2

:conv3
ren JPack.toc JPack.toc.3.0
ren JPack.toc.2.4 JPack.toc
goto end

:conv2
ren JPack.toc JPack.toc.3.0
ren JPack.toc.2.4 JPack.toc

:end